Know About Popular Waste to Energy Conversion Routes

Waste-to-energy is the use of combustion and biological technologies to recover energy from urban wastes. There are three major waste to energy conversion routes – thermochemical, biochemical and physico-chemical. Thermochemical conversion, characterized by higher temperature and conversion rates, is best suited for lower moisture feedstock and is generally less selective for products. On the other hand, biochemical technologies are more suitable for wet wastes which are rich in organic matter.

Teesside-WTE-plant

Thermochemical Conversion of Waste

The three principal methods of thermochemical conversion of waste are combustion in excess air, gasification in reduced air, and pyrolysis in the absence of air. The most common technique for producing both heat and electrical energy from household wastes is direct combustion.

Combined heat and power (CHP) or cogeneration systems, ranging from small-scale technology to large grid-connected facilities, provide significantly higher efficiencies than systems that only generate electricity.

WTE_Pathways

Combustion technology is the controlled combustion of waste with the recovery of heat to produce steam which in turn produces power through steam turbines. Pyrolysis and gasification represent refined thermal treatment methods as alternatives to incineration and are characterized by the transformation of the waste into product gas as energy carrier for later combustion in, for example, a boiler or a gas engine. Plasma gasification, which takes place at extremely high temperature, is also hogging limelight nowadays.

Biochemical Conversion of Waste

Biochemical processes, like anaerobic digestion, can also produce clean energy in the form of biogas which can be converted to power and heat using a gas engine. Anaerobic digestion is the natural biological process which stabilizes organic waste in the absence of air and transforms it into biofertilizer and biogas.

Anaerobic digestion is a reliable technology for the treatment of wet, organic waste.  Organic waste from various sources is biochemically degraded in highly controlled, oxygen-free conditions circumstances resulting in the production of biogas which can be used to produce both electricity and heat.

anaerobic_digestion_plant

In addition, a variety of fuels can be produced from waste resources including liquid fuels, such as ethanol, methanol, biodiesel, Fischer-Tropsch diesel, and gaseous fuels, such as hydrogen and methane. The resource base for biofuel production is composed of a wide variety of forestry and agricultural resources, industrial processing residues, and municipal solid and urban wood residues. Globally, biofuels are most commonly used to power vehicles, heat homes, and for cooking.

Physico-chemical Conversion of Waste

The physico-chemical conversion of waste involves various processes to improve physical and chemical properties of solid waste. The combustible fraction of the waste is converted into high-energy fuel pellets which may be used in steam generation.

RDF pellet

The waste is first dried to bring down the high moisture levels. Sand, grit, and other incombustible matter are then mechanically separated before the waste is compacted and converted into fuel pellets or RDF.

Fuel pellets have several distinct advantages over coal and wood because it is cleaner, free from incombustibles, has lower ash and moisture contents, is of uniform size, cost-effective, and eco-friendly.

Waste-to-Energy Sector in China: Perspectives

China is the world’s largest waste generator, producing as much as 175 million tons of waste every year. With a current population surpassing 1.37 billion and exponential trends in waste output expected to continue, it is estimated that China’s cities will need to develop an additional hundreds of landfills and waste-to-energy plants to tackle the growing waste management crisis.

garbage-china

China’s three primary methods for municipal waste management are landfills, incineration, and composting. Nevertheless, the poor standards and conditions they operate in have made waste management facilities generally inefficient and unsustainable. For example, discharge of leachate into the soil and water bodies is a common feature of landfills in China. Although incineration is considered to be better than landfills and have grown in popularity over the years, high levels of toxic emissions have made MSW incineration plants a cause of concern for public health and environment protection.

Prevalent Issues

Salman Zafar, a renowned waste management, waste-to-energy and bioenergy expert was interviewed to discuss waste opportunities in China. As Mr. Zafar commented on the current problems with these three primary methods of waste management used by most developing countries, he said, “Landfills in developing countries, like China and India, are synonymous with huge waste dumps which are characterized by rotting waste, spontaneous fires, toxic emissions and presence of rag-pickers, birds, animals and insects etc.” Similarly, he commented that as cities are expanding rapidly worldwide, it is becoming increasingly difficult to find land for siting new landfills.

On incineration, Zafar asserted that this type of waste management method has also become a controversial issue due to emission concerns and high technology costs, especially in developing countries. Many developers try to cut down costs by going for less efficient air pollution control systems”. Mr. Zafar’s words are evident in the concerns reflected in much of the data ­that waste management practices in China are often poorly monitored and fraudulent, for which data on emission controls and environmental protection is often elusive.

Similarly, given that management of MSW involves the collection, transportation, treatment and disposal of waste, Zafar explains why composting has also such a small number relative to landfills for countries like China. He says, “Composting is a difficult proposition for developing countries due to absence of source-segregation. Organic fraction of MSW is usually mixed with all sorts of waste including plastics, metals, healthcare wastes and industrial waste which results in poor quality of compost and a real risk of introduction of heavy metals into agricultural soils.”

Given that China’s recycling sector has not yet developed to match market opportunities, even current treatment of MSW calls for the need of professionalization and institutionalization of the secondary materials industry.

While MSW availability is not an issue associated with the potential of the resource given its dispersion throughout the country and its exponential increase throughout, around 50 percent of the studies analyzed stated concerns for the high moisture content and low caloric value of waste in China, making it unattractive for WTE processes.

Talking about how this issue can be dealt with, Mr. Zafar commented that a plausible option to increase the calorific value of MSW is to mix it with agricultural residues or wood wastes. Thus, the biomass resources identified in most of the studies as having the greatest potential are not only valuable individually but can also be processed together for further benefits.

Top Challenges

Among the major challenges on the other hand, were insufficient or elusive data, poor infrastructure, informal waste collection systems and the lack of laws and regulations in China for the industry. Other challenges included market risk, the lack of economic incentives and the high costs associated with biomass technologies. Nevertheless, given that the most recurring challenges cited across the data were related to infrastructure and laws and regulations, it is evident that China’s biomass policy is in extreme need of reform.

China’s unsustainable management of waste and its underutilized potential of MSW feedstock for energy and fuel production need urgent policy reform for the industry to develop. Like Mr. Zafar says, “Sustainable waste management demands an integration of waste reduction, waste reuse, waste recycling, and energy recovery from waste and landfilling. It is essential that China implements an integrated solid waste management strategy to tackle the growing waste crisis”.

Future Perspectives

China’s government will play a key role in this integrated solid waste management strategy. Besides increased cooperation efforts between the national government and local governments to encourage investments in solid waste management from the private sector and foster domestic recycling practices, first, there is a clear need to establish specialized regulatory agencies (beyond the responsibilities of the State Environmental Protection Administration and the Ministry of Commerce) that can provide clearer operating standards for current WTE facilities (like sanitary landfills and incinerators) as well as improve the supervision of them.

It is essential that China implements an integrated solid waste management strategy to tackle the growing waste crisis

It is essential that China implements an integrated solid waste management strategy to tackle the growing waste crisis

Without clear legal responsibility assigned to specialized agencies, pollutant emissions and regulations related to waste volumes and operating conditions may continue to be disregarded. Similarly, better regulation in MSW management for efficient waste collection and separation is needed to incentivize recycling at the individual level by local residents in every city. Recycling after all is complementary to waste-to-energy, and like Salman Zafar explains, countries with the highest recycling rates also have the best MSW to energy systems (like Germany and Sweden).

Nevertheless, without a market for reused materials, recycling will take longer to become a common practice in China. As Chinese authorities will not be able to stop the waste stream from growing but can reduce the rate of growth, the government’s role in promoting waste management for energy production and recovery is of extreme importance.

A Glance at Biggest Dumpsites in Nigeria

Waste dumping is the predominant method for solid waste disposal in developing countries worldwide, and Nigeria is no exception. Nigeria is home to six of the biggest dumpsites in Africa, according to Waste Atlas 2014 report on World’s 50 Biggest Dumpsites published by D-Waste. These dumpsites are located in three most important cities in Nigeria namely, Lagos, Port Harcourt and Ibadan.

Let us have a quick look at the major landfills in Nigeria:

Olusosun

Olusosun is the largest dumpsite not only in Lagos but in Nigeria and receives about 2.1 million tonnes of waste annually comprising mostly of municipal solid waste, construction waste, and electronic waste (e-waste). The dumpsite covers an area of about 43 hectares and it is 18 meters deep.

The dumpsite has been in existence since 1992 and has housed about 24.5 million tonnes of waste since then. A population of about 5 million people lives around 10km radius from the site and numerous health problems like skin irritation, dysentery, water-related diseases, nausea etc. have been reported by residents living around 3km radius from the site.

Solous 2

It is located in Lagos and occupies around 8 hectares of land along Lasu-Iba road. The dumpsite receives about 820,000 tonnes of waste annually and has since its existence in 2006 accepted around 5.8 million tonnes of MSW.

Solous is just 200 meters away from the nearest dwellings and almost 4 million people live within 10km radius from the site. Due to the vulnerable sand formation of the area, leachate produced at the dumpsite flows into groundwater causing its contamination.

Epe

Epe dumpsite also in Lagos occupies about 80 hectares of land. The dumpsite was opened in 2010 and has an annual input of 12,000 tonnes of MSW. Epe is the dumpsite which the Lagos State government is planning to upgrade to an engineered landfill and set to replace Olusosun dumpsite after its closure.

Since its existence, it has received about 47,000 tonnes of waste and it is just 500 meters away from the nearest settlement. The dumpsite is also just 2km away from Osogbo River and 7km away from Lekki Lagoon.

Awotan (Apete)

The dumpsite is located in Ibadan and has been in existence since 1998 receiving 36,000 tonnes of MSW annually. It covers an area of 14 hectares and already has in place almost 525,000 tonnes of waste.

The dumpsite is close to Eleyele Lake (2.5km away) and IITA Forest Reserve (4.5km away). The nearest settlement to the dumpsite is just 200 meters away and groundwater contamination has been reported by nearby residents.

Lapite

Lapite dumpsite is also located in Ibadan occupies an area of 20 hectares receiving around 9,000 tonnes of MSW yearly. Since its existence in 1998, it has housed almost 137,000 tonnes of MSW. It is 9km away from IITA Forest Reserve and surrounded by vegetations on both sides of the road since the dumpsite is directly opposite a major road.

Olusosun is the largest dumpsite in Nigeria

The nearest settlement is about 2km away but due to the heavy metals present in the leachate produced in the waste dump, its leakage poses a great threat to groundwater and biodiversity in the area.

Eneka

It is located in Port Harcourt, the commercial hub of South-South, Nigeria along Igwuruta/Eneka road and 9km from Okpoka River and Otamiri River. It receives around 45,600 tonnes of MSW annually and already has about 12 million tonnes of waste in place.

The site lies in an area of 5 hectares and it is flooded almost all year round as rainfall in the area exceeds 2,500mm per annum. Due to this and the resultant flow of the flood which would have mixed with dumpsite leachate; groundwater, surface water, and soil contamination affect the 1.2 million people living around 10km radius from the site as the nearest building is just 200 meters away.

Benefits of Eco-Friendly Junk Removal Services in 2022

With only nine years until the effects of climate change become irreversible, it is more important than ever that we are all doing as much as we can to look after our planet. One way to make a positive impact on the environment is to sign up with an eco-friendly junk removal service.

What is eco-friendly junk removal?

The goal of eco-friendly junk removal is to dispose of waste in an ecologically responsible way. This can mean different things depending on what service you choose to sign up with.

Some services will try to rehome goods such as unwanted clothing, furniture, and toys, whereas others, like J Dickinson and Sons, aim to recycle all waste in a safe and environmentally friendly way.

benefits of eco-friendly junk removal

Why should I use an eco-friendly junk removal service?

There are a whole host of reasons why you should consider using a reliable junk removal service, such as Stand Up Guys Junk Removal. First of all, it is a way of disposing of waste that is beneficial to the environment. It reduces the amount of waste that ends up in landfills. It is a preventative measure against global warming and that alone should sell the service to you.

Secondly, if your unwanted goods are being reused and donated to someone who may really value them, this feels morally better than just throwing things away. Instead, you are doing something good for someone else as well as doing something that will benefit the planet.

What to do in the absence of eco-friendly junk removal service

Eco-friendly junk removal does not have to be done via a service. You can make a big difference yourself with your waste.

Instead of throwing out old clothes that you no longer use, fill up a bag and take it down to your local charity shop. The same can be done with children’s toys, DVDs, books, bedding, and more.

If you have unwanted furniture items, instead of taking them to a dump or leaving them in a skip, try selling them at a reasonable price instead. Gumtree and Facebook Marketplace are excellent starting points if you are looking to sell any unwanted goods.

This puts some money into your pocket, and is a much more environmentally friendly way to dispose of something than simply throwing it away.

skip bins

You can also start upcycling your waste. Keep a space in your shed for scrap wood and metal, as you never know when it might come in handy. Start DIY projects and turn old items into something new and exciting.

A slightly shabby dining table can be sanded down, repainted and used outside. Use unwanted pots, pans, or even sinks as planters in your garden. With upcycling, you can go as far as your imagination takes you.

Conclusion

Eco junk removal is an excellent way to care for people and the planet. Donating or selling unwanted items benefits both yourself and others. Collection services are excellent as you know you have disposed of your goods in an environmentally responsible way. Upcycling allows your creative spirit to run free. There really is no reason not to get involved in eco-friendly junk removal this year.